Theorem bj-con2com 32548

Description: A commuted form of the contrapositive, true in minimal calculus. (Contributed by BJ, 19-Mar-2020.)

Assertion

Ref	Expression
bj-con2com	|- ( ph -> ( ( ps -> -. ph ) -> -. ps ) )

Proof of Theorem bj-con2com

Step	Hyp	Ref	Expression
1		con2 130	. 2 |- ( ( ps -> -. ph ) -> ( ph -> -. ps ) )
2	1	com12 32	1 |- ( ph -> ( ( ps -> -. ph ) -> -. ps ) )

Syntax hints:   -. wn 3   -> wi 4

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem is referenced by:  bj-con2comi  32549